Troubleshooting LAN Emulation Switching Environments

This chapter provides troubleshooting information for connectivity and performance problems in LAN emulation (LANE) switching environments. The ATM Forum defined the LANE specification so that legacy LAN users can take advantage of the benefits of ATM without requiring modifications to end-station hardware or software. For an overview of LANE on a switch router, refer to the "Configuring LAN Emulation" chapter in the ATM Switch Router Software Configuration Guide . For an overview of LANE on the Catalyst 5000 and 6000 ATM modules, refer to the "Configuring ATM LAN Emulation" chapter in the ATM Software Configuration Guide and Command Reference : Catalyst 5000 and 6000 ATM Modules.

Note The ATM addresses are examples only. The addresses on your switch might be different.

NoteEmulated LAN entities coexist on one or more Cisco routers or switch routers. On Cisco routers or switch routers, each LANE server and broadcast-and-unknown server is always a single entity. Other LANE components include switch routersthose that support the Integrated Local Management Interface (ILMI) and signalling. Multiple emulated LANs can coexist on a single ATM network.

Initial Troubleshooting of LANE

This section describes how to use the Internet Control Message Protocol (ICMP) ping command to test for connectivity between the switch router and either a router or an Ethernet switch.

To test for Ethernet connectivity, perform the following task:

Command

Purpose

ping ipip-address

Tests the configuration, using the ping command. The ping command sends an echo request to the host, which is specified in the command line.

Follow these steps to troubleshoot LANE connections:

Step 1 Use the ping command to confirm the connection between the switch router (EngFl1Ls1) and the Catalyst 5000 (EngFl1Cas1) in the engineering building:

Step 2 Check the Success rate field. It should indicate 100 percent. This indicates that the ICMP packet was sent and returned.

If the success rate is less than 100 percent, continue with the following test to determine the problem with the LANE configuration. Refer to the "Configuring LAN Emulation" chapter in theATM Switch Router Software Configuration Guide .

Checking Basic LANE Configuration

Use the following commands to test the LANE connection status and performance:

Command

Purpose

show lane default-atm-addresses

Shows the LANE default ATM address.

show lane

Shows the LANE connection status.

show lane client

Shows the LANE client connection status.

Follow these steps to confirm the LANE LECS, LES, and BUS configuration:

Step 1 Use the show lane default-atm-addresses command at the LANE component designated as the LECS, LES, and BUS to determine the addresses.

EngFl1Ls1# show lane default-atm-addresses

interface ATM13/0/0:

LANE Client: 47.00918100000000E04FACB401.00E04FACB402.**

LANE Server: 47.00918100000000E04FACB401.00E04FACB403.**

LANE Bus: 47.00918100000000E04FACB401.00E04FACB404.**

LANE Config Server: 47.00918100000000E04FACB401.00E04FACB405.00

note: ** is the subinterface number byte in hex

EngFl1Lsl#

Step 2 Use the show lane command to confirm the LANE configuration of the switch router.

Note This example show how to confirm the LANE configuration of a switch router. Use the same command to confirm the LANE configuration of a Catalyst 5000 or 6000 ATM module.

Step 3 Check the Admin (Administration) and State fields. The values should be up and operational, respectively.

Step 4 Check the ATM address of this LECS field. This ATM address should match the ATM address in the LANE configuration server displayed in Step 1.

Step 5 Within the LE BUS section of the display, check the ELAN name field. It should match the name configured. To determine the ELAN name, use the show lane database command and check the default ELAN field.

Step 6 Check the ATM Address field. This ATM address should match the address displayed in the LANE Server field shown in Step 1. The ATM address is appended with the corresponding subinterface number in hexadecimal.

Checking LANE Client Configuration

Use the following command to troubleshoot the LANE client connectivity:

Command

Purpose

show lane client

Shows the connection status of the LANE client.

Follow these steps to confirm the configuration and status of the LANE client:

Step 1 Use the show lane client command to confirm the LANE client.

Note This example shows how to confirm the LANE client configuration at ATM subinterface 13/0/0.1 on a switch router. Use the same command to confirm LANE client configurations on the Catalyst 5000 or 6000 ATM modules.

Note This same information appears in the previously described show lane command.

Step 2 Check the ELAN name field. This should match the ELAN name configured.

Step 3 Check the Admin and State fields. They should read up and operational, respectively.

If the Admin field shows "down", the interface or subinterface is administratively shut down. To reenable the interface, use the no shutdown command on the interface or subinterface.

Step 4 Check the Join Attempt field. A high number of join attempts might mean that the LECS is unreachable. To determine the status of the LECS, use the show lane config command.

Step 5 Check the Last Fail Reason field for any of the following messages:

Link went down

The problem is on the physical layer. Check the cable and the module quality. Physically loopback the interface and check the status using the show interfaces command.

Local config changed

The switch detected a configuration change. Force the LANE client to join the ELAN with the shutdown/no shutdown command sequence on the interface or subinterface.

Fail to set up config VC

The LANE client cannot establish a VCC to the LECS. This failure might be caused by ILMI, which must be enabled to provide the ATM address prefix. If ILMI is not functioning, no ATM address prefix is distributed and no SVCs can be established. Check the LANE component addresses using the show lane default-atm-addresses command. The following example shows correct output:

EngFl1Ls1#show lane default-atm-addresses

interface ATM13/0/0:

LANE Client: 47.00918100000000E0F75D0401.00E0F75D0402.**

LANE Server: 47.00918100000000E0F75D0401.00E0F75D0403.**

LANE Bus: 47.00918100000000E0F75D0401.00E0F75D0404.**

LANE Config Server: 47.00918100000000E0F75D0401.00E0F75D0405.00

note: ** is the subinterface number byte in hex

If ILMI is not suppling the ATM address prefix, the output appears as follows:

If the remote ATM switch is not a Cisco device, verify that the LECS address is advertised by ILMI. If it is not, use the well-known address of the LECS.

If the LECS ATM address is not explicitly configured on the LANE client switch, configure it with the atm lecs-address-default command.

If the LECS ATM address has been explicitly configured on the LANE client switch, compare the LECS ATM address on the LANE client switch, using the show lane client command, with the LECS ATM address on the switch hosting the LECS, using the show lane config command. Also check that the LECS is up and operational.

Receiving negative config response

The LECS refuses to connect to the ELAN. This is usually due to a configuration mistake, such as incorrectly specifying the ELAN type or name. Try the following actions to resolve the problem:

Check the LANE client ELAN type and name in the configuration, using the show lane client command. Remember that the ELAN names are case sensitive.

If the ELAN membership is restricted, use the show lane database command to verify that the LANE client ATM address is specified in the LANE database.

Use the show lane server command to verify that the LES connected to the LECS. The LES should have the same LECS ATM address information as a client.

Control Direct VC being released

The LANE client could not connect to the LES. The LES is either unreachable or misconfigured. If the LES address is hardcoded in the configuration, check the ATM address of the LES on the device where it is located, using the show lane server command. Compare that address with the ATM address configured for the LES on the LANE client switch, using the show lane database command.

Receiving negative join response

The LES refuses to connect. Try the following actions to resolve the problem:

If the ELAN is restricted, check the LANE database configuration, using the show lane database command, to ensure that it includes the ATM address of the LANE client.

If the LANE client and LES are configured on the same subinterface and the ATM address of the LES is explicitly configured with the lane server-atm-address command, the LANE client might be trying to contact a backup LES. These connection requests will be refused. Verify this with the show lane client and show lane server commands. To correct this situation, configure the LES on a different subinterface.

Step 6 Check the ATM Address column in the virtual channel circuit (VCC) configuration table. These ATM addresses should be propagated as follows:

Checking the Configuration Server Database

The LECS assigns individual clients to particular emulated LANs by directing them to the LANE server that corresponds to the emulated LAN. The LECS maintains a database of LANE client ATM or Media Access Control (MAC) addresses and their ELANs.

Note A LECS can serve multiple ELANs.

Use the following command in privileged EXEC mode to display the configuration of the LANE client database binding:

Command

Purpose

show lane database

Displays the LANE client database binding.

Follow these steps to confirm the configuration of the LANE database:

Step 1 Use the show lane database command to display the default binding of the LANE database of the switch router in the engineering building.

Step 2 Check the LANE Config Server database table field. It indicates the binding of the LANE client to the LANE database.

Step 3 Check the server field. The ATM address displayed should correspond to the ATM address shown in the show lane default-atm-addresses command in Step 1 of the previous section, "Checking Basic LANE Configuration."